Effects of HIF-1α-siRNA and CTM in U251MG and U343MG Cells: qRT-PCR of CA9 mRNA Levels. A (U251MG) and B (U343MG), Silencing of HIF-1α depleted the normoxic and hypoxic CA9 mRNA levels. CA9 mRNA levels using 75 nM HIF-1α-specific siRNA as compared to 75 nM control siRNA-treated and untreated cells. C (U251MG) and D (U343MG), CTM depleted the normoxic and hypoxic expression of CA9 mRNA. 75 nM CTM in comparison with DMSO-treated and untreated cells.